Secondary or recurrent dental caries remains a critical concern in the practice of contemporary dentistry. Various reports indicate that between 50% and 70% of the restorations placed annually are replacements of previous restorations due to the development of secondary caries adjacent to, or beneath the restorations. The ability to detect and diagnosed very early demineralization at restoration margins would allow for early intervention to stabilize or even reverse the disease process and thus eliminate or reduce the need for further invasive restorative procedures., The proposed investigation is designed to test two hypotheses: (1) quantified light fluorescence imaging procedures are capable of detecting very early secondary caries which cannot be detected with conventional visual-tactile methods; and (2) the use of innovative interventions to treat very early secondary caries will remineralize the adjacent enamel or prevent further progression of disease. To validate the early detection of methodology a two-year clinical study will be conducted in two different populations of children (8-11 years-of-age) who are in need of occlusal restorations in their deciduous molars. The teeth will be restored with either amalgam or resin and then examined for secondary caries at baseline and semi-annually thereafter using the conventional visual- tactile examination, quantified light fluorescence (QLF), infra-red laser fluorescence (IR), and electrical conductivity (EM). All exfoliated deciduous teeth will be collected, sectioned and examined by polarized light microscopy to validate and determine the accuracy of the various detection methods. The intervention study will use a similar clinical model with restorations placed in deciduous and permanent molars in need of restoration and these teeth will be examined semi-annually for evidence of secondary caries. Once QLF detects evidence of varies activity, it will be randomized to one of the intervention treatments and the treatment administered. Subsequent QLF examined will be performed to determine evidence of further disease activity or reversal (remineralization). The results of these studies will validate an instrumental method for the early detection of secondary caries and assess the impact of several innovative interventions for controlling early secondary caries.